Work vehicles, such as agricultural or industrial tractors, have an increasing number of electronic components and power distribution requirements. The power and data distribution occurs in a relatively harsh operating environment with moisture, vibration and heat transfer concerns. Typically, it is necessary to route electrical harnesses from devices (such as operator controls and displays) inside the vehicle cab through the vehicle bulkhead into the engine compartment, where many of the vehicle's electronic controllers are mounted. This “pass through” of data and power between the cab and engine compartment must be environmentally sealed to water and dust. A bulkhead mounted electronic module typically includes a mounting flange at one end thereof which fits into and hermetically seals with a hole in the bulkhead of the vehicle. The mounting flange is positioned at the end of the electronic module so that a small footprint is utilized at the connection location. The electronic module has a “cab side” and an “engine side” on opposite sides of the mounting flange, with plug-in electrical connectors specific to each side.
With a flange mounted electronic module as described above, only the plug-in connector(s) are exposed on the cab side of the bulkhead, and the electronic module is arranged in a cantilever manner on the engine side of the bulkhead. This works well for an electronic module with a sturdy metal “shell” or housing surrounding and enclosing the electronics inside. The metal housing provides enough rigidity to support the cantilevered electronic module and minimize vibration concerns.
An electronic module in the form of a power distribution module may also be flange mounted to the vehicle bulkhead. The power distribution module is essentially a “fuse panel” for the vehicle, containing fuses and relays used by the vehicle functions in both the cab and the engine compartment. A power distribution module passing through the bulkhead and cantilever arranged in the engine compartment provides access to both sides of the module, allowing access to harness connectors on one side, and the fuses and relays on the other side. However, because access must be provided to the fuses and relays so that they can be replaced as needed, a metal housing completely enclosing the module is not possible. The housing thus includes an access cover providing access to the fuses and relays on one side of the power distribution module.
With a cantilever mounted power distribution module as described above, vibrations can be a concern. Moreover, removal and insertion of the fuses and/or relays puts mechanical stresses on the printed circuit board (PCB) within the housing which carries the fuses and relays. These mechanical stresses can damage electrical traces and components on the PCB. Further, many of the electronic components used in power distribution can generate a substantial amount of heat which must be drawn away from the electronic components.
What is needed in the art is an electronic module which may be flange mounted to a bulkhead of a vehicle in a manner to alleviate moisture, vibration and heat transfer concerns, and provide a high level of reliability.